2波長レーザスペックル面内振動モード測定システムの改良

摘要

本論文では，測定精度と測定速度向上を目的として2波長レーザスペックル面内振動変位測定システムの改良を行った．具体的な改良点は，1）昨年の研究結果を基に干渉指数γを振動変位計算から除外し，変位推定精度を向上，2）2レーザを同時に照射できる光学系に変更，3）振動子駆動時および非駆動時のスペックル画像の2次元相関イメージから振動変位マップへの線型変換，の3点である．%Two-light-source laser speckle system for visualizing the in-plane mode shapes of high frequency piezoelectric resonators has been improved. Based on our previous reports, the measurement range of the vibration displacement was expanded by increasing the order of the polynomial approximation in the optical interference. A transformation from the 2D correlations between two laser-speckle images of the resonator-resting and -driving states to the vibration displacement maps was also developed. The performance gain of the measurement system using a combination of these improvements is demonstrated through the experimental results.